This invention relates to a master brake cylinder reservoir cap diaphragm assembly that prevents brake fluid from passing through but allows air to freely pass through.
Brake master cylinder reservoirs require a method of venting to atmosphere to prevent a build-up of pressure or a vacuum in the reservoir. This demand is becoming more challenging due to evolving technology. For instance, vehicles equipped with traction control systems need to draw fluid from the master cylinder reservoir quickly.
It is well known to use a diaphragm in connection with the cap used to close the brake master cylinder reservoir. Typically, the diaphragm is rubber and has a vent slit through which air can pass.
There are several disadvantages of this design. The vent geometry does not freely allow air to flow through and thus restricts the amount of brake fluid that can be pulled from the master cylinder reservoir. Further, energy is required to open the vent, which results in brake fluid movement delay. Also, brake fluid can leak out through the vent slit.
The present invention provides alternatives and advantages over the prior art by providing a master brake cylinder reservoir cap diaphragm assembly that allows air to freely pass through but limits brake fluid from passing through. Master cylinder reservoirs require a method of venting to atmosphere to prevent a build-up of pressure or a vacuum in the reservoir.
Preferably, the diaphragm assembly includes a flexible sealing component having an aperture and a fluid flow restrictive material that is bonded to the flexible sealing component covering the aperture. The flexible sealing component is preferably ring-shaped and flat. Further, the flexible sealing component preferably has a raised section for providing a seal.
The diaphragm assembly is positioned between the fill neck of the master brake cylinder reservoir and the cap that connects to the fill neck. The raised section on the flexible sealing component creates a seal between the diaphragm assembly and the cap. However, a small channel is preferably formed in the cap for the passage of air to and from atmosphere.